DKK1 is a predictive biomarker for response to DKN-01: Results of a phase 2 basket study in women with recurrent endometrial carcinoma.

PURPOSE: Dickkopf-1 (DKK1) is a Wnt signaling modulator promoting tumor growth, metastasis, angiogenesis, and immunosuppression by regulating innate immunity. DKK1 is over-expressed in gynecologic cancers and is associated with shortened survival. DKN-01 is a humanized monoclonal antibody with DKK1 neutralizing activity that may provide clinical benefit to patients whose tumors have overexpression of DKK1 or Wnt genetic alterations. METHODS: We conducted an open-label, Phase 2 basket study with 2-stage design in patients with endometrial carcinoma (EC) and platinum-resistant/refractory epithelial ovarian cancer. DKN-01 was administered either as monotherapy or in combination with weekly paclitaxel at investigator's discretion. All patients underwent NGS testing prior to enrollment; tumor tissue was also tested for DKK1 expression by RNAscope pre-treatment and after cycle 1 if available. At least 50% of patients were required to have a Wnt signaling alteration either directly or tangentially. This publication reports results from the EC population overall and by DKK1-expression. RESULTS: DKN-01 monotherapy and in combination with paclitaxel was more effective in patients with high DKK1-expressing tumors compared to low-expressing tumors. DKN-01 monotherapy demonstrated an objective response rate [ORR] of 25.0% vs. 0%; disease control rate [DCR] of 62.5% vs. 6.7%; median progression-free survival [PFS] was 4.3 vs. 1.8 months, and overall survival [OS] was 11.0 vs. 8.2 months in DKK1-high vs DKK1-low patients. Similarly, DKN-01 in combination with paclitaxel demonstrated greater clinical activity in patients with DKK1-high tumors compared to DKK1-low tumors: DCR was 55% vs. 44%; median PFS was 5.4 vs. 1.8 months; and OS was 19.1 vs. 10.1 months. Wnt activating mutations correlated with higher DKK1 expression. DKN-01 was well tolerated as a monotherapy and in combination with paclitaxel. CONCLUSIONS: Collectively, data demonstrates promising clinical activity of a well-tolerated drug, DKN-01, in EC patients with high tumoral DKK1 expression which frequently corresponded to the presence of a Wnt activating mutation. Future development will focus on using DKN-01 in DKK1-high EC patients in combination with immunotherapy.

A Phase 1/2 multicenter trial of DKN-01 as monotherapy or in combination with docetaxel for the treatment of metastatic castration-resistant prostate cancer (mCRPC).

BACKGROUND: Dickkopf-related protein 1 (DKK1) is a Wingless-related integrate site (Wnt) signaling modulator that is upregulated in prostate cancers (PCa) with low androgen receptor expression. DKN-01, an IgG4 that neutralizes DKK1, delays PCa growth in pre-clinical DKK1-expressing models. These data provided the rationale for a clinical trial testing DKN-01 in patients with metastatic castration-resistant PCa (mCRPC). METHODS: This was an investigator-initiated parallel-arm phase 1/2 clinical trial testing DKN-01 alone (monotherapy) or in combination with docetaxel 75 mg/m2 (combination) for men with mCRPC who progressed on ≥1 AR signaling inhibitors. DKK1 status was determined by RNA in-situ expression. The primary endpoint of the phase 1 dose escalation cohorts was the determination of the recommended phase 2 dose (RP2D). The primary endpoint of the phase 2 expansion cohorts was objective response rate by iRECIST criteria in patients treated with the combination. RESULTS: 18 pts were enrolled into the study-10 patients in the monotherapy cohorts and 8 patients in the combination cohorts. No DLTs were observed and DKN-01 600 mg was determined as the RP2D. A best overall response of stable disease occurred in two out of seven (29%) evaluable patients in the monotherapy cohort. In the combination cohort, five out of seven (71%) evaluable patients had a partial response (PR). A median rPFS of 5.7 months was observed in the combination cohort. In the combination cohort, the median tumoral DKK1 expression H-score was 0.75 and the rPFS observed was similar between patients with DKK1 H-score ≥1 versus H-score = 0. CONCLUSION: DKN-01 600 mg was well tolerated. DKK1 blockade has modest anti-tumor activity as a monotherapy for mCRPC. Anti-tumor activity was observed in the combination cohorts, but the response duration was limited. DKK1 expression in the majority of mCRPC is low and did not clearly correlate with anti-tumor activity of DKN-01 plus docetaxel.

Fludarabine plus alemtuzumab versus fludarabine alone in patients with previously treated chronic lymphocytic leukaemia: a randomised phase 3 trial.

BACKGROUND: Chronic lymphocytic leukaemia (CLL) is an incurable and chronic disorder, with worsening prognosis for patients as their disease progresses. We compared the efficacy and safety of the combination of fludarabine and alemtuzumab with fludarabine monotherapy in previously treated patients with relapsed or refractory CLL. METHODS: Patients (aged ≥ 18 years) with CLL Binet stage A, B, or C or Rai stages I-IV were randomly assigned in a 1:1 ratio according to a computer-generated allocation schedule to open-label combination treatment (fludarabine 30 mg/m(2) per day and alemtuzumab 30 mg per day on days 1-3) or monotherapy (fludarabine 25 mg/m(2) on days 1-5) by use of an interactive voice response system. Both regimens were given intravenously for a maximum of six 28-day cycles. The primary endpoint was progression-free survival (PFS). Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00086580. FINDINGS: Fludarabine plus alemtuzumab (n=168) resulted in better PFS than did fludarabine monotherapy (n=167; median 23·7 months [95% CI 19·2-28·4] vs 16·5 months [12·5-21·2]; hazard ratio 0·61 [95% CI 0·47-0·80]; p=0·0003) and overall survival (median not reached vs 52·9 months [40·9-not reached]; 0·65 [0·45-0·94]; p=0·021) compared with fludarabine alone. All-cause adverse events occurred in 161 (98%) of 164 patients in the combination treatment group and 149 (90%) of 165 in the fludarabine alone group. Patients in the fludarabine plus alemtuzumab group had more cytomegalovirus events (23 [14%] vs one [<1%]) and grade 1 or 2 potentially alemtuzumab infusion-related adverse reactions (102 [62%] vs 22 [13%]). Grade 3 or 4 toxicities in the combination treatment and monotherapy groups were leucopenia (121 [74%] of 164 vs 55 [34%] of 164), lymphopenia (149 [94%] of 158 vs 53 [33%] of 161), neutropenia (93 [59%] of 157 vs 110 [68%] of 161), thrombocytopenia (18 [11%] of 164 vs 27 [17%] of 163), and anaemia (14 [9%] of 163 vs 28 [17%] of 164). The incidence of serious adverse events was higher in the combination treatment group (54 [33%] of 164 vs 41 [25%] of 165); deaths due to adverse events were similar between the two groups (ten [6%] vs 12 [7%]). INTERPRETATION: The combination of fludarabine and alemtuzumab is another treatment option for patients with previously treated CLL. FUNDING: Genzyme.

Phase IB Study of GITR Agonist Antibody TRX518 Singly and in Combination with Gemcitabine, Pembrolizumab, or Nivolumab in Patients with Advanced Solid Tumors.

PURPOSE: TRX518 is a mAb engaging the glucocorticoid-induced TNF receptor-related protein (GITR). This open-label, phase I study (TRX518-003) evaluated the safety and efficacy of repeated dose TRX518 monotherapy and in combination with gemcitabine, pembrolizumab, or nivolumab in advanced solid tumors. PATIENTS AND METHODS: TRX518 monotherapy was dose escalated (Part A) and expanded (Part B) up to 4 mg/kg loading, 1 mg/kg every 3 weeks. Parts C-E included dose-escalation (2 and 4 mg/kg loading followed by 1 mg/kg) and dose-expansion (4 mg/kg loading) phases with gemcitabine (Part C), pembrolizumab (Part D), or nivolumab (Part E). Primary endpoints included incidence of dose-limiting toxicities (DLT), serious adverse events (SAE), and pharmacokinetics. Secondary endpoints were efficacy and pharmacodynamics. RESULTS: A total of 109 patients received TRX518: 43 (Parts A+B), 30 (Part C), 26 (Part D), and 10 (Part E), respectively. A total of 67% of patients in Parts D+E had received prior anti-PD(L)1 or anti-CTLA-4. No DLTs, treatment-related SAEs, and/or grade 4 or 5 AEs were observed with TRX518 monotherapy. In Parts C-E, no DLTs were observed, although TRX518-related SAEs were reported in 3.3% (Part C) and 10.0% (Part E), respectively. Objective response rate was 3.2%, 3.8%, 4%, and 12.5% in Parts A+B, C, D, and E, respectively. TRX518 affected peripheral and intratumoral regulatory T cells (Treg) with different kinetics depending on the combination regimen. Responses with TRX518 monotherapy+anti-PD1 combination were associated with intratumoral Treg reductions and CD8 increases and activation after treatment. CONCLUSIONS: TRX518 showed an acceptable safety profile with pharmacodynamic activity. Repeated dose TRX518 monotherapy and in combination resulted in limited clinical responses associated with immune activation. See related commentary by Hernandez-Guerrero and Moreno, p. 3905.

Safety, Efficacy, and Biomarker Results from a Phase Ib Study of the Anti-DKK1 Antibody DKN-01 in Combination with Pembrolizumab in Advanced Esophagogastric Cancers.

Therapeutic combinations targeting innate and adaptive immunity and predictive biomarkers of response in esophagogastric cancer (EGC) are needed. We assessed safety and clinical utility of DKN-01 (a novel DKK1-neutralizing IgG4 antibody) combined with pembrolizumab and retrospectively determined DKK1 tumoral expression as a biomarker. Patients with advanced EGC received intravenous DKN-01 (150 or 300 mg) on days 1 and 15 with pembrolizumab 200 mg on day 1 in 21-day cycles. Clinical response was assessed by RECIST v1.1. Association of tumoral DKK1 mRNA expression (H-score: high ≥ upper-tertile, low < upper-tertile) with response was assessed with PD-L1 levels as a covariate. Sixty-three patients received DKN-01 150 mg (n = 2) or 300 mg (n = 61) plus pembrolizumab. Common adverse events were fatigue, anemia, blood alkaline phosphatase elevation, aspartate aminotransferase elevation, and hyponatremia. Among evaluable anti-PD-1/PD-L1-naïve patients receiving DKN-01 300 mg and pembrolizumab, objective response rate (ORR) was 11.4% (5/44) and 18.5% (5/27) in patients with gastroesophageal junction or gastric cancer (GEJ/GC). Among response-evaluable anti-PD-1/PD-L1-naïve patients with GEJ/GC and known tumoral DKK1 expression, ORR was 50% in DKK1-high and 0% in DKK1-low patients, median PFS was 22.1 vs. 5.9 weeks (HR, 0.24; 95% CI, 0.08-0.67), respectively, and median OS was 31.6 weeks vs. 17.4 weeks (HR, 0.41; 95% CI, 0.16-1.07), respectively. Association of DKK1 expression with PFS was independent of PD-L1 expression (adjusted HR, 0.21; 95% CI, 0.06-0.69). DKN-01 combined with pembrolizumab was well tolerated with no new safety signals. Antitumor activity was enriched in anti-PD-1/PD-L1-naïve patients with GEJ/GC whose tumors expressed high DKK1.

Phase I and Biomarker Study of the Wnt Pathway Modulator DKN-01 in Combination with Gemcitabine/Cisplatin in Advanced Biliary Tract Cancer.

PURPOSE: Dickkopf-1 (DKK1) modulates Wnt signaling, promoting tumor growth, metastasis, and immunosuppression. High DKK1 expression has been detected in various tumor types-including biliary tract cancer (BTC)-and is associated with poor prognosis. DKN-01-a humanized mAb targeting DKK1-was evaluated in a phase I multicenter study in combination with gemcitabine and cisplatin in patients with unresectable or metastatic BTC with no prior systemic therapy for advanced disease. PATIENTS AND METHODS: This study included a dose-escalation phase assessing DKN-01 at two dose levels (150 mg and 300 mg) combined with gemcitabine (1,000 mg/m2) and cisplatin (25 mg/m2) followed by dose expansion. Primary endpoints evaluated safety and tolerability; secondary endpoints evaluated efficacy, pharmacokinetics, and circulating biomarkers. RESULTS: Fifty-one patients with intrahepatic cholangiocarcinoma (63%), extrahepatic cholangiocarcinoma (8%), and gallbladder cancer (29%) were enrolled. No dose-limiting toxicities were seen, and the expansion phase proceeded with DKN-01 300 mg (N = 47). The most frequent grade 3/4 treatment-emergent adverse events included neutropenia (60%), thrombocytopenia (34%), and anemia (23%). The objective response rate was 21.3% and median progression-free survival was 8.7 months (95% confidence interval, 5.4-10.3 months). Better outcomes were associated with biomarkers of angiogenesis inhibition (increased sVEGFR1 and lower VEGF-C) and reduced inflammation (lower IL6 and decreased TNFα). CONCLUSIONS: DKN-01 300 mg was well tolerated in this combination but did not appear to have additional activity beyond historically reported efficacy with gemcitabine/cisplatin alone. Exploratory pharmacokinetic and biomarker data indicate potential antiangiogenic and immunomodulatory activity of DKN-01/chemotherapy and the need for increased dose/intensity. A study with DKN-01 600 mg in combination with a PD-1 inhibitor in BTC is ongoing.

Dickkopf-1 Can Lead to Immune Evasion in Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: Metastatic castration-resistant prostate cancer (mCRPC) with low androgen receptor (AR) and without neuroendocrine signaling, termed double-negative prostate cancer (DNPC), is increasingly prevalent in patients treated with AR signaling inhibitors and is in need of new biomarkers and therapeutic targets. METHODS: Candidate genes enriched in DNPC were determined using differential gene expression analysis of discovery and validation cohorts of mCRPC biopsies. Laboratory studies were carried out in human mCRPC organoid cultures, prostate cancer (PCa) cell lines, and mouse xenograft models. Epigenetic studies were carried out in a rapid autopsy cohort. RESULTS: Dickkopf-1 (DKK1) expression is increased in DNPC relative to prostate-specific antigen (PSA)-expressing mCRPC in the Stand Up to Cancer/Prostate Cancer Foundation discovery cohort (11.2 v 0.28 reads per kilobase per million mapped reads; q < 0.05; n = 117) and in the University of Washington/Fred Hutchinson Cancer Research Center cohort (9.2 v 0.99 fragments per kilobase of transcript per million mapped reads; P < .0001). DKK1 expression can be regulated by activated Wnt signaling in vitro and correlates with activating canonical Wnt signaling mutations and low PSA mRNA in mCRPC biopsies (P < .05). DKK1 hypomethylation was associated with increased DKK1 mRNA expression (Pearson r = -0.66; P < .0001) in a rapid autopsy cohort (n = 7). DKK1-high mCRPC biopsies are infiltrated with significantly higher numbers of quiescent natural killer (NK) cells (P < .005) and lower numbers of activated NK cells (P < .0005). Growth inhibition of the human PCa model PC3 by the anti-DKK1 monoclonal antibody DKN-01 depends on the presence of NK cells in a severe combined immunodeficient xenograft mouse model. CONCLUSION: These results support DKK1 as a contributor to the immunosuppressive tumor microenvironment of DNPC. These data have provided the rationale for a clinical trial targeting DKK1 in mCRPC (ClinicalTrials.gov identifier: NCT03837353).

Rational design of anti-GITR-based combination immunotherapy.

Modulating T cell homeostatic mechanisms with checkpoint blockade can efficiently promote endogenous anti-tumor T cell responses1-11. However, many patients still do not benefit from checkpoint blockade12, highlighting the need for targeting of alternative immune pathways13. Glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) is an attractive target for immunotherapy, owing to its capacity to promote effector T cell (Teff) functions14,15 and hamper regulatory T cell (Treg) suppression16-20. On the basis of the potent preclinical anti-tumor activity of agonist anti-GITR antibodies, reported by us and others16,21,22, we initiated the first in-human phase 1 trial of GITR agonism with the anti-GITR antibody TRX518 ( NCT01239134 ). Here, we report the safety profile and immune effects of TRX518 monotherapy in patients with advanced cancer and provide mechanistic preclinical evidence to rationally combine GITR agonism with checkpoint blockade in future clinical trials. We demonstrate that TRX518 reduces circulating and intratumoral Treg cells to similar extents, providing an easily assessable biomarker of anti-GITR activity. Despite Treg reductions and increased Teff:Treg ratios, substantial clinical responses were not seen. Similarly, in mice with advanced tumors, GITR agonism was not sufficient to activate cytolytic T cells due to persistent exhaustion. We demonstrate that T cell reinvigoration with PD-1 blockade can overcome resistance of advanced tumors to anti-GITR monotherapy. These findings led us to start investigating TRX518 with PD-1 pathway blockade in patients with advanced refractory tumors ( NCT02628574 ).

Phase II trial of sequential chemotherapy followed by chemoradiation, surgery, and postoperative chemotherapy for the treatment of stage IIIA/IIIB non-small-cell lung cancer.

BACKGROUND: The optimal treatment of locally advanced non-small-cell lung cancer remains a challenge. Although the benefit of combined chemoradiation has been established, the optimal chemotherapy regimen, timing of full-dose chemotherapy, and how best to combine chemotherapy with radiation to maximize systemic and radiosensitizing effects remain unclear. PATIENTS AND METHODS: Twenty-nine patients with pathologically confirmed stage IIIA/IIIB non-small-cell lung cancer were included in a phase II trial of sequential carboplatin/paclitaxel followed by chemoradiation, surgery, and postoperative gemcitabine. Twenty-five patients (86%) completed the concurrent chemotherapy and radiation therapy phase and were eligible for surgery. At restaging, 7 patients (21%) showed disease progression. Seventeen patients (59%) went on to surgery. Few were able to tolerate full postoperative chemotherapy. RESULTS: The 1-year overall survival rate was 61%, with a 2-year survival rate of 56%. Median overall survival was 25.2 months. Seven of the patients are alive and without recurrence at the time of this writing. Our median follow-up time was 22.2 months. Reversible grade 3/4 toxicities were fairly common, experienced in 45% of patients. CONCLUSION: Our results with this combined modality approach are comparable with those of previous, similar studies. Postoperative chemotherapy after initial combined modality therapy is often not feasible, reinforcing the value of initial systemic therapy. Long-term results are still suboptimal and await studies adding targeted therapies to our usual chemotherapy/radiation approaches.

Alemtuzumab compared with chlorambucil as first-line therapy for chronic lymphocytic leukemia.

PURPOSE: We conducted a randomized trial to evaluate the efficacy and safety of intravenous alemtuzumab compared with chlorambucil in first-line treatment of chronic lymphocytic leukemia (CLL). PATIENTS AND METHODS: Patients received alemtuzumab (30 mg three times per week, for up to 12 weeks) or chlorambucil (40 mg/m(2) every 28 days, for up to 12 months). The primary end point was progression-free survival (PFS). Secondary end points included overall response rate (ORR), complete response (CR), time to alternative therapy, safety, and overall survival. RESULTS: We randomly assigned 297 patients, 149 to alemtuzumab and 148 to chlorambucil. Alemtuzumab had superior PFS, with a 42% reduction in risk of progression or death (hazard ratio [HR] = 0.58; P = .0001), and a median time to alternative treatment of 23.3 versus 14.7 months for chlorambucil (HR = 0.54; P = .0001). The ORR was 83% with alemtuzumab (24% CR) versus 55% with chlorambucil (2% CR); differences in ORR and CR were highly statistically significant (P < .0001). Elimination of minimal residual disease occurred in 11 of 36 complete responders to alemtuzumab versus none to chlorambucil. Adverse events profiles were similar, except for more infusion-related and cytomegalovirus (CMV) events with alemtuzumab and more nausea and vomiting with chlorambucil. CMV events had no apparent impact on efficacy. CONCLUSION: As first-line treatment for patients with CLL, alemtuzumab demonstrated significantly improved PFS, time to alternative treatment, ORR and CR, and minimal residual disease-negative remissions compared with chlorambucil, with predictable and manageable toxicity.